clean/data

# Changelog

## 2.3.1

- update documentation and project dependecies

## 2.3.0

- feature: Collection class has new method 'extend' that allow to concatenate two collections

## 2.2.3

- bugfix: invalid return type annotation in Collection methods

## 2.2.2

- bugfix: Collection::getElementMovedByOffset is not throwing exception for non-numeric (indexed) collection

## 2.2.1

- update phpdoc comments

## 2.2.0

- modify: one element collection will now support isset method

## 2.1.0

- feature: new `getBy` method added to Collection to retrive collection of entities matching criteria defined in callback